> On Mon, Apr 23, 2001 at 05:06:48PM +0100, Matt wrote:> > I'm writing a char device driver for a dsp card that drives a motion> > platform.>> Can you elaborate on the dsp card? Is it freely programmable? I'm> working on a project to support this kind of stuff via a> dedicated subsystem for Linux.

Very interesting... The emu10k1 driver (SBLive!) that will appearshortly in acXX will support loading code to it's DSP. It's a verysimple chip with only 16 instructions but it can generatehardware interrupts, DMA to host memory, 32 bit math. The maximumprogram size is 512 instructions (64 bits each) and can make use of 256registers (32 bits).

Is there a web page for your project?

> The problem is, that it's hard to get access to such cards. So> development is moving very slow :-(

I've used this method in some of my drivers. It works just fine, butas everybody already told you, you should do some checking on the valuesyou are passed from user space.

> What do you want to do with the buffers? If you plan to expose> them to user space, this is just plain wrong.>> If you use it only inside the kernel, please check that you avoid> using more than PAGE_SIZE as rxlen/txlen. Do scatter-gather> instead and vmalloc(). Either in the driver or by hardware> features.>> Regards>> Ingo Oeser>